JP2014152335A - Adhesive polymer composition and its application - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive polymer composition and its application.SOLUTION: The problem is solved by providing an adhesive polymer composition containing an acrylic resin (A) having a structure of the formula (I), where Ris a hydrogen atom or a methyl group, Ris a C1 to C10 alkyl group, or the formula (II), where a is an integer of 1 to 100; hydroxyl group-containing olefin acid alkyl ester (B) having a structure of the formula (III), where Ris a hydrogen atom or a methyl group; and a polymerization initiator (C), and having the hydroxyl group-containing olefine acid alkyl ester (B) of 2 to 25 pts.wt. and the polymerization initiator (C) of 0.5 to 5 pts.wt. based on 100 pts.wt. of the acrylic resin (A).

Description

  The present disclosure relates to an adhesive polymer composition, and more specifically to an adhesive polymer composition applicable to an image display device.

  In image display devices, the components are typically adhered to each other by an adhesive polymeric material. However, image display device components typically have a low surface polarity, whereas adhesive polymeric materials have a high polarity surface. In order to improve the adhesive strength between the polymer material and the component, it is customary to reduce the surface polarity of the polymer material by reducing the amount of polar functional group of the polymer material, and to improve the surface polarity of the component of the image display device. To increase the adhesive strength between them.

  While the adhesive strength between the polymer material and the component has been effectively increased by such a technique, the hydrophilicity of the polymer material is reduced when its polarity is reduced. Therefore, when the image display device is placed in a high-temperature and high-humidity environment, fogging may occur between the components of the image display device, and the performance may be degraded.

  In view of the above situation, there is a need for an adhesive polymer composition that improves the defects of conventional adhesive polymers.

  Therefore, in one aspect of the present disclosure, an adhesive polymer composition comprising an acrylic resin (A), a hydroxyl group-containing olefinic acid alkyl ester (B), and a polymerization initiator (C) is provided.

  In another aspect of the present disclosure, an adhesive polymer that can effectively reduce the haze increase rate of an image display device is provided.

  In a further aspect of the present disclosure, an adhesive material made with the adhesive polymer composition is provided.

  In a further aspect of the present disclosure, an adhesive material made with the adhesive polymer is provided.

  In a further aspect of the present disclosure, there is provided an image display device comprising a first transparent component, a second transparent component and an adhesive layer, wherein the adhesive layer is made of the material. The adhesive layer can effectively suppress the haze increase rate of the image display device in a high-temperature and high-humidity environment, and can reduce the resistance increase rate of the image display device without corroding the electrode layer of the image display device.

According to the above aspects of the present disclosure, an adhesive polymer composition is provided. In one embodiment, the adhesive polymer composition comprises an acrylic resin (A), a hydroxyl group-containing olefinic acid alkyl ester (B), and a polymerization initiator (C). The acrylic resin (A) has a structure of the formula (I).

In the formula (I), R ₁ is hydrogen or a methyl group, and R ₂ is a C1-C10 alkyl group or a structure of the formula (II).

In formula (II), a is an integer of 1-100.

The hydroxyl group-containing olefinic acid alkyl ester (B) has a surface energy in the range of 40 to 57 mJ / m ² and a structure of the formula (III).

In the formula (III), R ₁ is hydrogen or a methyl group.

  The hydroxyl group-containing olefinic acid alkyl ester (B) is 2 to 25 parts by weight and the polymerization initiator (C) is 0.5 to 5 parts by weight with respect to 100 parts by weight of the acrylic resin (A). .

  According to one aspect of the present disclosure, the hydroxyl group-containing olefinic acid alkyl ester (B) is hydroxyethyl methacrylate or hydroxyethyl acrylate.

According to another aspect of the present disclosure, an adhesive polymer is provided. In one embodiment, the adhesive polymer has a structure of formula (IV).

In the formula (IV), R ₁ is hydrogen or a methyl group, R ₂ is a C1-C10 alkyl group, b is an integer of 1-10, c is an integer of 500-2000, The adhesive polymer has a refractive index in the range of 1.46 to 1.52.

  According to one aspect of the present disclosure, the adhesive polymer has an acid value of 3 or less.

According to a further aspect of the present disclosure, an adhesive polymer is provided. In one embodiment, the adhesive polymer has a structure of formula (V).

In the formula (V), R ₁ is hydrogen or a methyl group, d is an integer of 30 to 250, and R ₃ has the structure of the formula (VI).

In the formula (VI), a is an integer of 1 to 100, and the adhesive polymer has a refractive index in the range of 1.46 to 1.52.

  According to one aspect of the present disclosure, the adhesive polymer has an acid value of 3 or less.

  According to a further aspect of the present disclosure, an adhesive material is provided. In one embodiment, the adhesive material is made of the adhesive polymer composition.

  According to a further aspect of the present disclosure, an adhesive material is provided. In one embodiment, the adhesive material is made of the adhesive polymer.

  According to a further aspect of the present disclosure, an image display device is provided. In one aspect, the image display device includes a first transparent component, a second transparent component, and an adhesive layer. The first transparent component may be a first glass, a first touch sensor element, a first thin film, or a first plastic plate. The second transparent component may be a second glass, a second touch sensor element, a second thin film, a second plastic plate, or a display element. The adhesive layer is disposed between the first transparent component and the second transparent component. The adhesive layer is made of the adhesive material.

  According to one aspect of the present disclosure, the image display device has a haze increase rate of 1% or less after 500 hours when placed in an environment having a temperature of 80 ° C. and a humidity of 90%.

  Applying the adhesive polymer composition of the present disclosure, which can improve the hydrophilicity of the adhesive polymer by adding a hydroxyl group-containing olefinic acid alkyl ester, increases the adhesive strength between the adhesive polymer and the transparent part. The haze increase rate of the image display device in a high temperature and high humidity environment can be suppressed. Next, by using an acrylic resin having a low acid value as a main component of the adhesive polymer composition of the present disclosure, the electrode layer of the image display device is prevented from corroding, and the performance of the image display device can be improved. .

  The present disclosure can be more fully understood by reading the following detailed description of the embodiments with reference to the accompanying drawings, in which:

FIG. 1 is a cross-sectional view of an image display device according to an aspect of the present disclosure.

  Hereinafter, the manufacture and use of aspects of the present disclosure will be described in detail. However, it can be understood that the aspects provide many applicable inventive concepts, which can be implemented in a variety of specific contexts. The particular aspects described are for illustrative purposes only and are not intended to limit the scope of the present disclosure.

  The present disclosure provides an adhesive polymer. Based on the various crosslink densities of the polymer chains in the adhesive polymer, glue and adhesive can each be formed, where the crosslink density of the glue is greater than 70% and less than 100% Yes, the crosslink density of the adhesive is 40% or more and 70% or less. As used herein, the term “glue” refers to an adhesive polymer that is cured at ambient temperature (for example, 15 to 35 ° C.) and cannot be repeatedly bonded, and the term “adhesive” is used herein. , An adhesive polymer that is cured at ambient temperature (eg, 15-35 ° C.) and can be repeatedly bonded. Furthermore, the term “initial” below is based on optical property measurements performed immediately after forming the adhesive polymer or image display device and is not affected by the high temperature and humidity environment, “Initial” refers to a temperature of 20-30 ° C. and a humidity of 55-65%.

  Next, the term “haze” in the present disclosure is the percentage of the scattered light flux with respect to the transmitted light flux when light passes through the measurement target. Therefore, when the measurement target has a multilayer structure and the refractive index difference between the layers is large, the scattered light flux increases and the transmitted light flux decreases, so the haze of the measurement target increases. In contrast, when the refractive index between layers is small, the haze of the measurement object is low.

The present disclosure provides an adhesive polymer composition comprising an acrylic resin (A), a hydroxyl group-containing olefinic acid alkyl ester (B), and a polymerization initiator (C). The acrylic resin (A) has a structure of the formula (I).

In the formula (I), R ₁ is hydrogen or a methyl group, and R ₂ is a C1-C10 alkyl group or a structure of the formula (II).

In formula (II), a is an integer of 1-100.

The hydroxyl group-containing olefinic acid alkyl ester (B) has a structure of the formula (III).

In the formula (III), R ₁ is hydrogen or a methyl group.

  The hydroxyl group-containing olefinic acid alkyl ester (B) is 2 to 25 parts by weight with respect to 100 parts by weight of the acrylic resin (A). Since the hydroxyl group-containing olefinic acid alkyl ester (B) has a hydroxyl group, the hydrophilicity of the adhesive polymer can be improved. Therefore, the moisture between the transparent parts can exist in the form of a water film so as not to affect the light transparency, thereby reducing the haze of the image display device. When the hydroxyl group-containing olefinic acid alkyl ester (B) is less than 2 parts by weight, the hydrophilicity of the adhesive polymer is not sufficient to make the water form a water film, thus reducing the antifogging property of the adhesive polymer. Resulting in. When the hydroxyl group-containing olefinic acid alkyl ester (B) is more than 25 parts by weight, the haze of the image display device can be effectively reduced, but the production cost of the adhesive polymer increases.

The hydroxyl group-containing olefinic acid alkyl ester (B) has a surface energy in the range of 40 to 57 mJ / m ² . When the surface energy of the hydroxyl group-containing olefinic acid alkyl ester (B) is less than 40 mJ / m ² , the hydrophilicity of the adhesive polymer is lowered, and the antifogging property is reduced. If the surface energy of the hydroxyl group-containing olefinic acid alkyl ester (B) is greater than 57 mJ / m ² , the hydrophilicity becomes too large, so that the electricity in the adhesive polymer increases, the electric capacity decreases, and the electric field transmission Affect the performance. Therefore, the adhesive polymer is not applicable to an image display device.

  In one embodiment, the hydroxyl group-containing olefinic acid alkyl ester (B) is hydroxyethyl methacrylate, hydroxyethyl acrylate, other suitable hydroxyl group-containing olefinic acid alkyl ester (B), or a combination thereof. In another embodiment, the hydroxyl group-containing olefinic acid alkyl ester (B) is produced with equal proportions of hydroxyethyl methacrylate and hydroxyethyl acrylate.

  A polymerization initiator (C) is 0.5-5 weight part with respect to 100 weight part of acrylic resins (A). The polymerization initiator (C) is used for polymerizing the acrylic resin (A) and the hydroxyl group-containing olefinic acid alkyl ester (B). When the polymerization initiator (C) is less than 0.5 parts by weight, the degree of polymerization of the adhesive polymer becomes insufficient, so that the adhesive polymer cannot be bonded. When there are more polymerization initiators (C) than 5 weight part, since the polymerization degree of an adhesive polymer will become high too much, the adhesive strength of an adhesive polymer will reduce.

A particular embodiment of the adhesive polymer of the present disclosure may be a structure of formula (IV) or (V).

In the formula (IV), R ₁ is hydrogen or a methyl group, R ₂ is a C1-C10 alkyl group, b is an integer of 1-10, and c is an integer of 500-2000.

In the formula (V), R ₁ is hydrogen or a methyl group, d is an integer of 30 to 250, and R ₃ has the structure of the formula (VI).

  The adhesive polymer of the present disclosure is produced with the above adhesive polymer composition. The acid value of the adhesive polymer is 3 or less, the initial haze is 1% or less, the total light transmittance is 99% or more, and the refractive index is in the range of 1.46 to 1.52. When the refractive index of the adhesive polymer is smaller than 1.46 or larger than 1.52, when light passes through the image display device, the scattered light flux increases and the transmitted light flux decreases due to the refractive index difference. The haze of the image display device increases.

When the acid value of the adhesive polymer is greater than 3, the electrode layer of the image display device is corroded by the acrylic group of the adhesive polymer, so that its resistance increases and affects its performance. See Table 1. Table 1 shows the acid value and the resistance increase rate of the methacrylic acid ester copolymers of Examples 1 to 3 and Comparative Examples 1 to 3. In addition, the acid value of the methacrylic acid ester copolymer of each Example is measured by the CNS 14906 petroleum product acid value test method (potentiometric titration method). The resistance increase rate shown in Table 1 is obtained by applying the methacrylic ester copolymer in each Example and Comparative Example to a polyethylene terephthalate (PET) film or glass having a size of 6 cm × 10 cm. The polymer was obtained by bonding 10 cm × 10 cm indium tin oxide (ITO) glass, leaving two 2 cm × 10 cm test areas on both sides of the ITO glass. Subsequently, ITO glass, PET film or glass is packaged to form a test device, and the resistance value (Z _si ) of the test device is measured by a multimeter.

Further, a control test device was manufactured using the same manufacturing material and the same manufacturing method as the above test device, except that the methacrylate ester copolymer was not applied between the ITO glass and the PET film or glass. Similarly, the resistance value (Z _bi ) of the control test device was measured with a multimeter.

The test device and control test device were then placed in an environment of temperature 80 ° C. and humidity 90%. After 500 hours, the resistances of the test device and the control test device were measured, and the resistance increase rate was calculated by the following formula (VII).

In formula (VII), Z _sf is the resistance of the test device after treatment in the hot and humid environment, and Z _bf is the resistance of the control test device after treatment in the hot and humid environment.

As shown in Table 1, when the acid value of the methacrylic acid ester was higher than 3, the resistance increase rate of the test device was larger than 10%. From the above, when the acid value of the methacrylic acid ester is higher than 3, the electrode layer of the image display device may be corroded by the acidic group of the adhesive polymer, and the device performance may be affected.

  Please refer to FIG. 1, which is a cross-sectional view of an image display device according to one aspect of the present disclosure. In one aspect, the image display device 100 includes a first transparent component 110, a second transparent component 120, an adhesive layer 130, and a packaging adhesive 140. The first transparent component 110 may be a first glass, a first touch sensor element, a first thin film, or a first plastic plate. The second transparent component 120 may be a second glass, a second touch sensor element, a second thin film, a second plastic plate, or a display element. In one aspect, the first transparent component 110 may be the same as or different from the second transparent component 120. The adhesive layer 130 is disposed between the first transparent part 110 and the second transparent part 120 and is made of an adhesive material made of the adhesive polymer composition. The packaging adhesive 140 is used to package the image display device 100 and isolate it from the effects of ambient moisture and oxygen.

  The initial haze of the image display device 100 is 1% or less. When the image display device 100 is placed in an environment having a temperature of 80 ° C. and a humidity of 90%, the haze increase rate is 1% or less after 500 hours. In one embodiment, the haze increase rate of the image display device 100 is equal to 0%.

  The following aspects are used to illustrate the application of the present disclosure, but are not limited thereto. It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the scope or spirit of the disclosure.

Preparation of adhesive polymer
Example 1
100 parts by weight of acrylic resin (model TSH02, manufactured by Soken Chemical Co., Ltd .; hereinafter referred to as A-1), 2 parts by weight of hydroxyl group-containing olefinic acid alkyl ester (B) and 0.5 parts by weight of polyisocyanate (Soken Chemical Co., Ltd.) A company manufactured; hereinafter referred to as C-1) was stirred and mixed at room temperature (for example, 25 ° C.). After 30 minutes, the adhesive polymer of Example 1 was obtained, wherein the hydroxyl group-containing olefinic acid alkyl ester (B) was composed of hydroxyethyl acrylate (hereinafter referred to as B-1) and hydroxyethyl methacrylate (hereinafter referred to as B-2). Are mixed at an equal ratio.

Examples 2-6, Comparative Examples 1-9
The preparation methods of Examples 2-6 and Comparative Examples 1-9 were the same as the preparation method of Example 1 except that various types and amounts of adhesive polymers were used. Moreover, since prescription is described in Table 2, it abbreviate | omits here.

Production of Adhesive Layer and Image Display Device The adhesive polymer was dissolved in a solvent to form an adhesive material. This adhesive material was applied to a release film and then dried at 105 ° C. to remove the solvent, and another release film was adhered to the dried adhesive material to form an adhesive layer. Then, the two release films on the adhesive layer were removed, and the adhesive layer was adhered between two glasses and packaged with a packaging adhesive to form an image display device. The obtained adhesive layer or image display device was evaluated by the following evaluation method, and the results are shown in Table 2. Refractive index, initial optical properties, appearance, yellowing test, adhesive strength, initial haze of image display device, image display The method for testing the haze increase rate of the device will be described later.

Evaluation method
1. Refractive index First, an auxiliary piece of 14 to 40 mm × 6 to 8 mm was placed on an Abbe refractometer (manufactured by Atago Co., Ltd., model DR-M2 / 1550). The smooth and bright surface of the auxiliary piece was pointed to the prism, and light entered from the matte surface so that the light entering the auxiliary piece was as perpendicular to the smooth surface as possible. A suitable contact liquid having a higher refractive index than the test sample was selected. Subsequently, after opening the second prism and dropping a droplet of contact liquid, a 40 mm × 8 mm adhesive layer was placed on the refractometer. The adhesive layer was moved so that the contact liquid was distributed over the contact surface. The light source was aligned and the boundary line was adjusted to the intersection of the intersection lines to obtain the value displayed on the instrument screen, which was taken as the refractive index. The results are shown in Table 2.

2. Initial optical properties A haze meter made by Nippon Denshoku Industries Co., Ltd. was used to evaluate the haze of the initial optical properties and the total light transmittance of the adhesive layer. The adhesive layer had a thickness of 100 μm and was evaluated based on the following criteria.
Hayes:
○: Haze ≦ 1%.
X: 1% <haze.
Total light transmittance:
A: 99% ≦ total light transmittance.
X: Total light transmittance <99%.

3. Bubble defect First, the image display device was placed in an oven manufactured by ESPEC CORP. Set to an oven temperature of 0 ° C. and a humidity of 90%. After 500 hours, the adhesive layer of the image display device was visually observed to confirm whether or not a bubble defect occurred and evaluated based on the following criteria.
○: No bubble defect ×: Bubble defect

4). Evaluation of shrinkage shrinkage was the same as the evaluation method of bubble defects. The difference was that the shrinkage rate was evaluated by the following formula (VIII).
In Formula (VIII), L _i is the length of the adhesive layer of the image display device before baking, and L _f is the length of the adhesive layer of the image display device after baking, according to the following criteria: evaluated.
○: Shrinkage ratio ≦ 3%.
X: 3% <shrinkage rate.

5. The yellowing test image display device was placed in a UV weathering chamber (model QUV-SE, manufactured by Q-Lab) set at a temperature of 60 ° C. and an irradiation efficiency of 0.89 W. After irradiation for 500 hours, the b value of the adhesive layer was measured using a spectrophotometer (model UV-2450, manufactured by Shimadzu Corporation) and evaluated according to the following criteria.
○: b <0.2.
X: 0.2 <= b.

6). An adhesive layer having a width of adhesive strength of 25 mm was adhered to a PET film having a thickness of 100 μm, and a 2 kg roller was rolled twice thereon to bring the adhesive layer and the PET film into intimate contact. Next, pressurization defoaming was performed, but the temperature was set to 23 ° C. and the pressure was set to 0.5 MPa. After 20 minutes, the sample containing the adhesive layer and the PET film was placed in an environment having a temperature of 23 ° C. and a humidity of 65% for 24 hours. Subsequently, using a tensile testing machine manufactured by Shimadzu Corporation, the tensile strength was set to 300 mm / min and the tensile angle was set to 180 °, and the adhesive strength of the optical adhesive layer having a width of 25 mm was tested. And evaluated.
A: 4N / 25 mm <adhesion strength.
X: Adhesive strength ≦ 4 N / 25 mm.

7). The initial haze and haze increase rate of the image display device were measured in the environment of 20 ° C. to 30 ° C. and 55% to 65% humidity with the haze meter. Thereafter, the image display device was placed in an environment of a temperature of 80 ° C. and a humidity of 90%. After 500 hours, the haze of the image display device is measured with a haze meter, and when the initial haze is subtracted from this haze, the haze increase rate is obtained.

  Refer to Table 2. Table 2 shows the compositions, composition ratios, and evaluation results of the examples and comparative examples.

  According to the result of Table 2, compared with Comparative Example 8, the hydroxyl group-containing olefinic acid alkyl ester (B) of Examples 4 to 6 can suppress the haze increase rate of the image display device in a high-temperature and high-humidity environment. When the hydroxyl group-containing olefinic acid alkyl ester (B) is less than 2 parts by weight or more than 25 parts by weight and the polymerization initiator (C) is less than 0.5 parts by weight or more than 5 parts by weight, The haze increase rate of the image display device in a high-temperature and high-humidity environment cannot be suppressed, and the device performance has deteriorated.

  Furthermore, according to the results of Comparative Examples 1 and 2, when the adhesive polymer does not contain the hydroxyl group-containing olefinic acid alkyl ester (B), fogging occurs in the image display device in a high-temperature and high-humidity environment, and the use of the image display device The performance has deteriorated.

Comparative Example 10
The preparation method of Comparative Example 10 was the same as that of Example 1. In Comparative Example 10, 100 parts by weight of an acrylic resin (manufactured by East Green Technology, model R728, hereinafter referred to as A-3), 2 parts by weight of a hydroxyl group-containing olefinic acid alkyl ester (B), 3 parts by weight of a polymerization initiator ( C-2; CIBA, model C-184) and 3 parts by weight of another polymerization initiator (C-3; CIBA, model TPO) were polymerized to form an adhesive polymer. Comparative Example 10 had a refractive index of 1.53, and the haze characteristic evaluated by the above evaluation method was x.

  In view of the examples of the present disclosure, the adhesive polymer of the present disclosure is improved in the hydrophilicity of the adhesive polymer by adding a hydroxyl group-containing olefinic acid alkyl ester (B), thereby displaying an image in a hot and humid environment. The haze increase rate of the device can be suppressed, the adhesive strength between the adhesive polymer and the transparent component can be maintained, and the performance of the image display device can be improved.

  Next, in order to prevent corrosion of the electrode layer of the image display device from the acid functional group of the adhesive polymer by using a low acid value acrylic resin as a main component of the adhesive polymer composition of the present disclosure, The rate of increase in resistance can be reduced.

  Although the present disclosure has been described in considerable detail with reference to certain aspects, other aspects are possible. Accordingly, the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein.

  It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present disclosure without departing from the scope or spirit of the disclosure. In view of the above circumstances, modifications and changes of the present disclosure are intended to be included in the present disclosure so long as they fall within the scope of the following claims.

Claims (10)

Formula (I)
(In the formula (I), R ₁ is hydrogen or a methyl group, R ₂ is a C1-C10 alkyl group or a formula (II)
(In the formula (II), a is an integer of 1 to 100)
Is the structure of
An acrylic resin (A) having the structure:
It has a surface energy in the range of 40-57 mJ / m ² and also has the formula (III):
(In the formula (III), R ₁ is hydrogen or a methyl group)
A hydroxyl group-containing olefinic acid alkyl ester (B) having the structure:
An adhesive polymer composition comprising a polymerization initiator (C),
The hydroxyl group-containing olefinic acid alkyl ester (B) is 2 to 25 parts by weight and the polymerization initiator (C) is 0.5 to 5 parts by weight with respect to 100 parts by weight of the acrylic resin (A). Adhesive polymer composition.   The adhesive polymer composition according to claim 1, wherein the hydroxyl group-containing olefinic acid alkyl ester (B) is hydroxyethyl methacrylate or hydroxyethyl acrylate. Formula (IV)
(In the formula, R ₁ is hydrogen or a methyl group, R ₂ is a C1-C10 alkyl group, b is an integer of 1-10, and c is an integer of 500-2000).
And an adhesive polymer having a refractive index in the range of 1.46 to 1.52.   The adhesive polymer according to claim 3, wherein the adhesive polymer has an acid value of 3 or less. Formula (V)
(In the formula (V), R ₁ is hydrogen or a methyl group, d is an integer of 30 to 250, and R ₃ is the formula (VI)
(In the formula (VI), a is an integer of 1 to 100)
Having the structure of
And an adhesive polymer having a refractive index in the range of 1.46 to 1.52.   The adhesive polymer according to claim 5, wherein the adhesive polymer has an acid value of 3 or less.   An adhesive material made of the adhesive polymer composition according to claim 1.   The adhesive material manufactured with the adhesive polymer as described in any one of Claims 3-6. A first transparent component that is a first glass, a first touch sensor element, a first thin film or a first plastic plate;
A second glass, a second touch sensor element, a second thin film, a second plastic plate or a second transparent component which is a display element;
An image display device comprising: an adhesive layer made of an adhesive material according to claim 7 or 8 disposed between the first transparent component and the second transparent component.   The image display device according to claim 9, wherein the image display device is disposed in an environment having a temperature of 80 ° C. and a humidity of 90%, and has a haze increase rate of 1% or less after 500 hours.